More southern lands only assured the long term continuation of slavery.
It would cause war with Mexico and enhance slave power.
Britain
Yes. Most slaves were acquired since 1848 (when Mexico lost the territory after the Mexican-American War) during periodic raids against Native American settlements. Most slaves were brought to Las Cruces, Alamogordo and Santa Fe. New Mexico also was admitted as a slave territory as part of a compromise to prevent the American Civil War, but it never hold more than a dozen black slaves, as Native American slaves were much easier to acquire and transport. In 1862 the US Congress outlawed slavery on all US territories, including New Mexico.
Generally speaking, the Left-wing in the US tends to oppose participation in wars.
No
Americans believed that the Mexicans started the War because they "Shed American blood, on American Soil"- President James Polk....but really American troops crossed the border were on Mexico's territory.
US Civil War
us won the war with mexico
Freed African Americans would take some of their jobs, the workers were socially higher than slaves, and disruption of the Union.
Many slaves had served in the Civil War. There were about 4 million slaves under bondage by the end of the Civil War.
There were no slaves at the time of World War 2.
What did zimmermann propose that Mexico do if war between Germany and the us